fs/nfs/fscache.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /* NFS filesystem cache interface definitions
   3  *
   4  * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #ifndef _NFS_FSCACHE_H
   9 #define _NFS_FSCACHE_H
  10
  11 #include <linux/nfs_fs.h>
  12 #include <linux/nfs_mount.h>
  13 #include <linux/nfs4_mount.h>
  14 #include <linux/fscache.h>
  15
  16 #ifdef CONFIG_NFS_FSCACHE
  17
  18 /*
  19  * set of NFS FS-Cache objects that form a superblock key
  20  */
  21 struct nfs_fscache_key {
  22         struct rb_node          node;
  23         struct nfs_client       *nfs_client;    /* the server */
  24
  25         /* the elements of the unique key - as used by nfs_compare_super() and
  26          * nfs_compare_mount_options() to distinguish superblocks */
  27         struct {
  28                 struct {
  29                         unsigned long   s_flags;        /* various flags
  30                                                          * (& NFS_MS_MASK) */
  31                 } super;
  32
  33                 struct {
  34                         struct nfs_fsid fsid;
  35                         int             flags;
  36                         unsigned int    rsize;          /* read size */
  37                         unsigned int    wsize;          /* write size */
  38                         unsigned int    acregmin;       /* attr cache timeouts */
  39                         unsigned int    acregmax;
  40                         unsigned int    acdirmin;
  41                         unsigned int    acdirmax;
  42                 } nfs_server;
  43
  44                 struct {
  45                         rpc_authflavor_t au_flavor;
  46                 } rpc_auth;
  47
  48                 /* uniquifier - can be used if nfs_server.flags includes
  49                  * NFS_MOUNT_UNSHARED  */
  50                 u8 uniq_len;
  51                 char uniquifier[0];
  52         } key;
  53 };
  54
  55 /*
  56  * Definition of the auxiliary data attached to NFS inode storage objects
  57  * within the cache.
  58  *
  59  * The contents of this struct are recorded in the on-disk local cache in the
  60  * auxiliary data attached to the data storage object backing an inode.  This
  61  * permits coherency to be managed when a new inode binds to an already extant
  62  * cache object.
  63  */
  64 struct nfs_fscache_inode_auxdata {
  65         s64     mtime_sec;
  66         s64     mtime_nsec;
  67         s64     ctime_sec;
  68         s64     ctime_nsec;
  69         u64     change_attr;
  70 };
  71
  72 /*
  73  * fscache-index.c
  74  */
  75 extern struct fscache_netfs nfs_fscache_netfs;
  76 extern const struct fscache_cookie_def nfs_fscache_server_index_def;
  77 extern const struct fscache_cookie_def nfs_fscache_super_index_def;
  78 extern const struct fscache_cookie_def nfs_fscache_inode_object_def;
  79
  80 extern int nfs_fscache_register(void);
  81 extern void nfs_fscache_unregister(void);
  82
  83 /*
  84  * fscache.c
  85  */
  86 extern void nfs_fscache_get_client_cookie(struct nfs_client *);
  87 extern void nfs_fscache_release_client_cookie(struct nfs_client *);
  88
  89 extern void nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
  90 extern void nfs_fscache_release_super_cookie(struct super_block *);
  91
  92 extern void nfs_fscache_init_inode(struct inode *);
  93 extern void nfs_fscache_clear_inode(struct inode *);
  94 extern void nfs_fscache_open_file(struct inode *, struct file *);
  95
  96 extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
  97 extern int nfs_fscache_release_page(struct page *, gfp_t);
  98
  99 extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
 100                                        struct inode *, struct page *);
 101 extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
 102                                         struct inode *, struct address_space *,
 103                                         struct list_head *, unsigned *);
 104 extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
 105
 106 /*
 107  * wait for a page to complete writing to the cache
 108  */
 109 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 110                                                   struct page *page)
 111 {
 112         if (PageFsCache(page))
 113                 fscache_wait_on_page_write(nfsi->fscache, page);
 114 }
 115
 116 /*
 117  * release the caching state associated with a page if undergoing complete page
 118  * invalidation
 119  */
 120 static inline void nfs_fscache_invalidate_page(struct page *page,
 121                                                struct inode *inode)
 122 {
 123         if (PageFsCache(page))
 124                 __nfs_fscache_invalidate_page(page, inode);
 125 }
 126
 127 /*
 128  * Retrieve a page from an inode data storage object.
 129  */
 130 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 131                                             struct inode *inode,
 132                                             struct page *page)
 133 {
 134         if (NFS_I(inode)->fscache)
 135                 return __nfs_readpage_from_fscache(ctx, inode, page);
 136         return -ENOBUFS;
 137 }
 138
 139 /*
 140  * Retrieve a set of pages from an inode data storage object.
 141  */
 142 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 143                                              struct inode *inode,
 144                                              struct address_space *mapping,
 145                                              struct list_head *pages,
 146                                              unsigned *nr_pages)
 147 {
 148         if (NFS_I(inode)->fscache)
 149                 return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
 150                                                     nr_pages);
 151         return -ENOBUFS;
 152 }
 153
 154 /*
 155  * Store a page newly fetched from the server in an inode data storage object
 156  * in the cache.
 157  */
 158 static inline void nfs_readpage_to_fscache(struct inode *inode,
 159                                            struct page *page,
 160                                            int sync)
 161 {
 162         if (PageFsCache(page))
 163                 __nfs_readpage_to_fscache(inode, page, sync);
 164 }
 165
 166 /*
 167  * Invalidate the contents of fscache for this inode.  This will not sleep.
 168  */
 169 static inline void nfs_fscache_invalidate(struct inode *inode)
 170 {
 171         fscache_invalidate(NFS_I(inode)->fscache);
 172 }
 173
 174 /*
 175  * Wait for an object to finish being invalidated.
 176  */
 177 static inline void nfs_fscache_wait_on_invalidate(struct inode *inode)
 178 {
 179         fscache_wait_on_invalidate(NFS_I(inode)->fscache);
 180 }
 181
 182 /*
 183  * indicate the client caching state as readable text
 184  */
 185 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 186 {
 187         if (server->fscache)
 188                 return "yes";
 189         return "no ";
 190 }
 191
 192 #else /* CONFIG_NFS_FSCACHE */
 193 static inline int nfs_fscache_register(void) { return 0; }
 194 static inline void nfs_fscache_unregister(void) {}
 195
 196 static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 197 static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 198
 199 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
 200
 201 static inline void nfs_fscache_init_inode(struct inode *inode) {}
 202 static inline void nfs_fscache_clear_inode(struct inode *inode) {}
 203 static inline void nfs_fscache_open_file(struct inode *inode,
 204                                          struct file *filp) {}
 205
 206 static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 207 {
 208         return 1; /* True: may release page */
 209 }
 210 static inline void nfs_fscache_invalidate_page(struct page *page,
 211                                                struct inode *inode) {}
 212 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
 213                                                   struct page *page) {}
 214
 215 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
 216                                             struct inode *inode,
 217                                             struct page *page)
 218 {
 219         return -ENOBUFS;
 220 }
 221 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
 222                                              struct inode *inode,
 223                                              struct address_space *mapping,
 224                                              struct list_head *pages,
 225                                              unsigned *nr_pages)
 226 {
 227         return -ENOBUFS;
 228 }
 229 static inline void nfs_readpage_to_fscache(struct inode *inode,
 230                                            struct page *page, int sync) {}
 231
 232
 233 static inline void nfs_fscache_invalidate(struct inode *inode) {}
 234 static inline void nfs_fscache_wait_on_invalidate(struct inode *inode) {}
 235
 236 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 237 {
 238         return "no ";
 239 }
 240
 241 #endif /* CONFIG_NFS_FSCACHE */
 242 #endif /* _NFS_FSCACHE_H */